This invention relates to fluid organopolysiloxanes which are capable of vulcanizing at room temperature upon exposure to moisture to rubbery materials and to organofunctional tris(ketoximino) silane crosslinking agents, chain-extending agents and chain-terminating agents, useful in such compositions.
Generally, prior art room temperature vulcanizable materials (RTV's) comprise a linear polymer and a crosslinking agent.
Some of the prior art crosslinking agents which have commercial success are either solid at room temperature, unstable at room temperature, or both. A disadvantage of the prior art crosslinking agents which are solid at room temperature is that they must be heated to the liquid state prior to use. Crosslinking agents which are unstable at room temperature must be maintained under refrigeration prior to use. Failure to maintain the materials under refrigeration results in disproportionation, and a defective product.
U.S. Pat. No. 3,714,089 to Hamilton et al, incorporated herein by reference, discloses an improved crosslinking agent for room temperature vulcanizing compositions, which are not burdened with the disadvantages of the prior art crosslinking agents. A representative crosslinking agent within the scope of Hamilton et al is acetoxyethyltriacetoxysilane.
Although the room temperature vulcanized compositions of Hamilton et al are particularly well suited for many bonding applications, as a result of the liberation of acetic acid during the curing mechanism, they are not particularly well suited for applications in conjunction with substrates such as concrete, wherein the liberated acetic acid or other deleterious material is corrosive or otherwise detrimental.